Do you think it would benefit me to gain muscle mass?

[rhilllakefield]

Bruce lee was a huge advocate of heavy weight training. He was actually an avid bodybuilder.

I would find the ideal weight for your body, and maintain that weight at the lowest bodyfat percentage possible.

I find that my body is happy at 165-170 lbs. Any lower, and I feel like my strength is off, and any heavier and my speed and endurance suffer.

Your body will be different. I would say, don't push it beyond the range where you can train at your best at.